A study led by an Emory University researcher concludes that an organic diet given to children provides a "dramatic and immediate protective effect" against exposures to two pesticides that are commonly used in U.S. agricultural production. The results were published on a recent online version of the scientific journal Environmental Health Perspectives (EHP). Over a fifteen-day period, Dr. Chensheng "Alex" Lu and his colleagues from Emory University, the University of Washington, and the Centers for Disease Control and Prevention specifically measured the exposure of two organophosphorus pesticides (OP) - malathion and chlorpyrifos - in 23 elementary students in the Seattle area by testing their urine.

The participants, ages 3-11-years-old, were first monitored for three days on their conventional diets before the researchers substituted most of the children's conventional diets with organic food items for five consecutive days. The children were then re-introduced to their normal foods and monitored for an additional seven days.

"Immediately after substituting organic food items for the children's normal diets, the concentration of the organophosphorus pesticides found in their bodies decreased substantially to non-detectable levels until the conventional diets were re-introduced," says Dr. Lu, an assistant professor in the department of environmental and occupational health, Rollins School of Public Health, Emory University.

During the days when children consumed organic diets, most of their urine samples contained zero concentration for the malathion metabolite. However, once the children returned to their conventional diets, the average malathion metabolite concentration increased to 1.6 parts per billion with a concentration range from 5 to 263 parts per billion, Dr. Lu explains.

A similar trend was observed for chlorpyrifos. The average chlorpyrifos metabolite concentration increased from one part per billion during the organic diet days to six parts per billion when children consumed conventional food.

The researchers note that to ensure that any detectable change in dietary pesticide exposure would be attributable to the organic food rather than the change in diet, the substituted organic foods were items the children would have normally eaten as part of their conventional diet. Organic food items were substituted for the conventional diet of fresh fruits and vegetables, juices, processed fruits or vegetables (e.g. salsa), and wheat-based or corn-based products (i.e. pasta, cereal, popcorn, or chips).

Former research has linked organophosphorus pesticides to causes of neurological effects in animals and humans.

"Recent regulatory changes aiming to minimize children's exposures to pesticides have either banned or restricted the use of many organophosphorus pesticides in the residential environment. However, fewer restrictions have been imposed in agriculture," Dr. Lu says.

According to the annual survey by U.S. Department of Agriculture Pesticide Data Program, organophosphorus pesticide residues are still routinely detected in food items that are commonly consumed by young children.

The study was funded by the United States Environmental Protection Agency.

The Environmental Health Perspectives (EHP) is an open access journal published by the National Institute of Environmental Health Sciences. The full article is available at http://ehp.niehs.nih.gov/docs/2005/8418/abstract.html.